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1/*
2 * POWERNV cpufreq driver for the IBM POWER processors
3 *
4 * (C) Copyright IBM 2014
5 *
6 * Author: Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 */
19
20#define pr_fmt(fmt) "powernv-cpufreq: " fmt
21
22#include <linux/kernel.h>
23#include <linux/sysfs.h>
24#include <linux/cpumask.h>
25#include <linux/module.h>
26#include <linux/cpufreq.h>
27#include <linux/smp.h>
28#include <linux/of.h>
29#include <linux/reboot.h>
30#include <linux/slab.h>
31#include <linux/cpu.h>
32#include <trace/events/power.h>
33
34#include <asm/cputhreads.h>
35#include <asm/firmware.h>
36#include <asm/reg.h>
37#include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
38#include <asm/opal.h>
39#include <linux/timer.h>
40
41#define POWERNV_MAX_PSTATES 256
42#define PMSR_PSAFE_ENABLE (1UL << 30)
43#define PMSR_SPR_EM_DISABLE (1UL << 31)
44#define PMSR_MAX(x) ((x >> 32) & 0xFF)
45#define LPSTATE_SHIFT 48
46#define GPSTATE_SHIFT 56
47#define GET_LPSTATE(x) (((x) >> LPSTATE_SHIFT) & 0xFF)
48#define GET_GPSTATE(x) (((x) >> GPSTATE_SHIFT) & 0xFF)
49
50#define MAX_RAMP_DOWN_TIME 5120
51/*
52 * On an idle system we want the global pstate to ramp-down from max value to
53 * min over a span of ~5 secs. Also we want it to initially ramp-down slowly and
54 * then ramp-down rapidly later on.
55 *
56 * This gives a percentage rampdown for time elapsed in milliseconds.
57 * ramp_down_percentage = ((ms * ms) >> 18)
58 * ~= 3.8 * (sec * sec)
59 *
60 * At 0 ms ramp_down_percent = 0
61 * At 5120 ms ramp_down_percent = 100
62 */
63#define ramp_down_percent(time) ((time * time) >> 18)
64
65/* Interval after which the timer is queued to bring down global pstate */
66#define GPSTATE_TIMER_INTERVAL 2000
67
68/**
69 * struct global_pstate_info - Per policy data structure to maintain history of
70 * global pstates
71 * @highest_lpstate_idx: The local pstate index from which we are
72 * ramping down
73 * @elapsed_time: Time in ms spent in ramping down from
74 * highest_lpstate_idx
75 * @last_sampled_time: Time from boot in ms when global pstates were
76 * last set
77 * @last_lpstate_idx, Last set value of local pstate and global
78 * last_gpstate_idx pstate in terms of cpufreq table index
79 * @timer: Is used for ramping down if cpu goes idle for
80 * a long time with global pstate held high
81 * @gpstate_lock: A spinlock to maintain synchronization between
82 * routines called by the timer handler and
83 * governer's target_index calls
84 */
85struct global_pstate_info {
86 int highest_lpstate_idx;
87 unsigned int elapsed_time;
88 unsigned int last_sampled_time;
89 int last_lpstate_idx;
90 int last_gpstate_idx;
91 spinlock_t gpstate_lock;
92 struct timer_list timer;
93};
94
95static struct cpufreq_frequency_table powernv_freqs[POWERNV_MAX_PSTATES+1];
96static bool rebooting, throttled, occ_reset;
97
98static const char * const throttle_reason[] = {
99 "No throttling",
100 "Power Cap",
101 "Processor Over Temperature",
102 "Power Supply Failure",
103 "Over Current",
104 "OCC Reset"
105};
106
107enum throttle_reason_type {
108 NO_THROTTLE = 0,
109 POWERCAP,
110 CPU_OVERTEMP,
111 POWER_SUPPLY_FAILURE,
112 OVERCURRENT,
113 OCC_RESET_THROTTLE,
114 OCC_MAX_REASON
115};
116
117static struct chip {
118 unsigned int id;
119 bool throttled;
120 bool restore;
121 u8 throttle_reason;
122 cpumask_t mask;
123 struct work_struct throttle;
124 int throttle_turbo;
125 int throttle_sub_turbo;
126 int reason[OCC_MAX_REASON];
127} *chips;
128
129static int nr_chips;
130static DEFINE_PER_CPU(struct chip *, chip_info);
131
132/*
133 * Note:
134 * The set of pstates consists of contiguous integers.
135 * powernv_pstate_info stores the index of the frequency table for
136 * max, min and nominal frequencies. It also stores number of
137 * available frequencies.
138 *
139 * powernv_pstate_info.nominal indicates the index to the highest
140 * non-turbo frequency.
141 */
142static struct powernv_pstate_info {
143 unsigned int min;
144 unsigned int max;
145 unsigned int nominal;
146 unsigned int nr_pstates;
147} powernv_pstate_info;
148
149/* Use following macros for conversions between pstate_id and index */
150static inline int idx_to_pstate(unsigned int i)
151{
152 if (unlikely(i >= powernv_pstate_info.nr_pstates)) {
153 pr_warn_once("index %u is out of bound\n", i);
154 return powernv_freqs[powernv_pstate_info.nominal].driver_data;
155 }
156
157 return powernv_freqs[i].driver_data;
158}
159
160static inline unsigned int pstate_to_idx(int pstate)
161{
162 int min = powernv_freqs[powernv_pstate_info.min].driver_data;
163 int max = powernv_freqs[powernv_pstate_info.max].driver_data;
164
165 if (min > 0) {
166 if (unlikely((pstate < max) || (pstate > min))) {
167 pr_warn_once("pstate %d is out of bound\n", pstate);
168 return powernv_pstate_info.nominal;
169 }
170 } else {
171 if (unlikely((pstate > max) || (pstate < min))) {
172 pr_warn_once("pstate %d is out of bound\n", pstate);
173 return powernv_pstate_info.nominal;
174 }
175 }
176 /*
177 * abs() is deliberately used so that is works with
178 * both monotonically increasing and decreasing
179 * pstate values
180 */
181 return abs(pstate - idx_to_pstate(powernv_pstate_info.max));
182}
183
184static inline void reset_gpstates(struct cpufreq_policy *policy)
185{
186 struct global_pstate_info *gpstates = policy->driver_data;
187
188 gpstates->highest_lpstate_idx = 0;
189 gpstates->elapsed_time = 0;
190 gpstates->last_sampled_time = 0;
191 gpstates->last_lpstate_idx = 0;
192 gpstates->last_gpstate_idx = 0;
193}
194
195/*
196 * Initialize the freq table based on data obtained
197 * from the firmware passed via device-tree
198 */
199static int init_powernv_pstates(void)
200{
201 struct device_node *power_mgt;
202 int i, nr_pstates = 0;
203 const __be32 *pstate_ids, *pstate_freqs;
204 u32 len_ids, len_freqs;
205 u32 pstate_min, pstate_max, pstate_nominal;
206
207 power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
208 if (!power_mgt) {
209 pr_warn("power-mgt node not found\n");
210 return -ENODEV;
211 }
212
213 if (of_property_read_u32(power_mgt, "ibm,pstate-min", &pstate_min)) {
214 pr_warn("ibm,pstate-min node not found\n");
215 return -ENODEV;
216 }
217
218 if (of_property_read_u32(power_mgt, "ibm,pstate-max", &pstate_max)) {
219 pr_warn("ibm,pstate-max node not found\n");
220 return -ENODEV;
221 }
222
223 if (of_property_read_u32(power_mgt, "ibm,pstate-nominal",
224 &pstate_nominal)) {
225 pr_warn("ibm,pstate-nominal not found\n");
226 return -ENODEV;
227 }
228 pr_info("cpufreq pstate min %d nominal %d max %d\n", pstate_min,
229 pstate_nominal, pstate_max);
230
231 pstate_ids = of_get_property(power_mgt, "ibm,pstate-ids", &len_ids);
232 if (!pstate_ids) {
233 pr_warn("ibm,pstate-ids not found\n");
234 return -ENODEV;
235 }
236
237 pstate_freqs = of_get_property(power_mgt, "ibm,pstate-frequencies-mhz",
238 &len_freqs);
239 if (!pstate_freqs) {
240 pr_warn("ibm,pstate-frequencies-mhz not found\n");
241 return -ENODEV;
242 }
243
244 if (len_ids != len_freqs) {
245 pr_warn("Entries in ibm,pstate-ids and "
246 "ibm,pstate-frequencies-mhz does not match\n");
247 }
248
249 nr_pstates = min(len_ids, len_freqs) / sizeof(u32);
250 if (!nr_pstates) {
251 pr_warn("No PStates found\n");
252 return -ENODEV;
253 }
254
255 powernv_pstate_info.nr_pstates = nr_pstates;
256 pr_debug("NR PStates %d\n", nr_pstates);
257 for (i = 0; i < nr_pstates; i++) {
258 u32 id = be32_to_cpu(pstate_ids[i]);
259 u32 freq = be32_to_cpu(pstate_freqs[i]);
260
261 pr_debug("PState id %d freq %d MHz\n", id, freq);
262 powernv_freqs[i].frequency = freq * 1000; /* kHz */
263 powernv_freqs[i].driver_data = id;
264
265 if (id == pstate_max)
266 powernv_pstate_info.max = i;
267 else if (id == pstate_nominal)
268 powernv_pstate_info.nominal = i;
269 else if (id == pstate_min)
270 powernv_pstate_info.min = i;
271 }
272
273 /* End of list marker entry */
274 powernv_freqs[i].frequency = CPUFREQ_TABLE_END;
275 return 0;
276}
277
278/* Returns the CPU frequency corresponding to the pstate_id. */
279static unsigned int pstate_id_to_freq(int pstate_id)
280{
281 int i;
282
283 i = pstate_to_idx(pstate_id);
284 if (i >= powernv_pstate_info.nr_pstates || i < 0) {
285 pr_warn("PState id %d outside of PState table, "
286 "reporting nominal id %d instead\n",
287 pstate_id, idx_to_pstate(powernv_pstate_info.nominal));
288 i = powernv_pstate_info.nominal;
289 }
290
291 return powernv_freqs[i].frequency;
292}
293
294/*
295 * cpuinfo_nominal_freq_show - Show the nominal CPU frequency as indicated by
296 * the firmware
297 */
298static ssize_t cpuinfo_nominal_freq_show(struct cpufreq_policy *policy,
299 char *buf)
300{
301 return sprintf(buf, "%u\n",
302 powernv_freqs[powernv_pstate_info.nominal].frequency);
303}
304
305struct freq_attr cpufreq_freq_attr_cpuinfo_nominal_freq =
306 __ATTR_RO(cpuinfo_nominal_freq);
307
308static struct freq_attr *powernv_cpu_freq_attr[] = {
309 &cpufreq_freq_attr_scaling_available_freqs,
310 &cpufreq_freq_attr_cpuinfo_nominal_freq,
311 NULL,
312};
313
314#define throttle_attr(name, member) \
315static ssize_t name##_show(struct cpufreq_policy *policy, char *buf) \
316{ \
317 struct chip *chip = per_cpu(chip_info, policy->cpu); \
318 \
319 return sprintf(buf, "%u\n", chip->member); \
320} \
321 \
322static struct freq_attr throttle_attr_##name = __ATTR_RO(name) \
323
324throttle_attr(unthrottle, reason[NO_THROTTLE]);
325throttle_attr(powercap, reason[POWERCAP]);
326throttle_attr(overtemp, reason[CPU_OVERTEMP]);
327throttle_attr(supply_fault, reason[POWER_SUPPLY_FAILURE]);
328throttle_attr(overcurrent, reason[OVERCURRENT]);
329throttle_attr(occ_reset, reason[OCC_RESET_THROTTLE]);
330throttle_attr(turbo_stat, throttle_turbo);
331throttle_attr(sub_turbo_stat, throttle_sub_turbo);
332
333static struct attribute *throttle_attrs[] = {
334 &throttle_attr_unthrottle.attr,
335 &throttle_attr_powercap.attr,
336 &throttle_attr_overtemp.attr,
337 &throttle_attr_supply_fault.attr,
338 &throttle_attr_overcurrent.attr,
339 &throttle_attr_occ_reset.attr,
340 &throttle_attr_turbo_stat.attr,
341 &throttle_attr_sub_turbo_stat.attr,
342 NULL,
343};
344
345static const struct attribute_group throttle_attr_grp = {
346 .name = "throttle_stats",
347 .attrs = throttle_attrs,
348};
349
350/* Helper routines */
351
352/* Access helpers to power mgt SPR */
353
354static inline unsigned long get_pmspr(unsigned long sprn)
355{
356 switch (sprn) {
357 case SPRN_PMCR:
358 return mfspr(SPRN_PMCR);
359
360 case SPRN_PMICR:
361 return mfspr(SPRN_PMICR);
362
363 case SPRN_PMSR:
364 return mfspr(SPRN_PMSR);
365 }
366 BUG();
367}
368
369static inline void set_pmspr(unsigned long sprn, unsigned long val)
370{
371 switch (sprn) {
372 case SPRN_PMCR:
373 mtspr(SPRN_PMCR, val);
374 return;
375
376 case SPRN_PMICR:
377 mtspr(SPRN_PMICR, val);
378 return;
379 }
380 BUG();
381}
382
383/*
384 * Use objects of this type to query/update
385 * pstates on a remote CPU via smp_call_function.
386 */
387struct powernv_smp_call_data {
388 unsigned int freq;
389 int pstate_id;
390 int gpstate_id;
391};
392
393/*
394 * powernv_read_cpu_freq: Reads the current frequency on this CPU.
395 *
396 * Called via smp_call_function.
397 *
398 * Note: The caller of the smp_call_function should pass an argument of
399 * the type 'struct powernv_smp_call_data *' along with this function.
400 *
401 * The current frequency on this CPU will be returned via
402 * ((struct powernv_smp_call_data *)arg)->freq;
403 */
404static void powernv_read_cpu_freq(void *arg)
405{
406 unsigned long pmspr_val;
407 s8 local_pstate_id;
408 struct powernv_smp_call_data *freq_data = arg;
409
410 pmspr_val = get_pmspr(SPRN_PMSR);
411
412 /*
413 * The local pstate id corresponds bits 48..55 in the PMSR.
414 * Note: Watch out for the sign!
415 */
416 local_pstate_id = (pmspr_val >> 48) & 0xFF;
417 freq_data->pstate_id = local_pstate_id;
418 freq_data->freq = pstate_id_to_freq(freq_data->pstate_id);
419
420 pr_debug("cpu %d pmsr %016lX pstate_id %d frequency %d kHz\n",
421 raw_smp_processor_id(), pmspr_val, freq_data->pstate_id,
422 freq_data->freq);
423}
424
425/*
426 * powernv_cpufreq_get: Returns the CPU frequency as reported by the
427 * firmware for CPU 'cpu'. This value is reported through the sysfs
428 * file cpuinfo_cur_freq.
429 */
430static unsigned int powernv_cpufreq_get(unsigned int cpu)
431{
432 struct powernv_smp_call_data freq_data;
433
434 smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
435 &freq_data, 1);
436
437 return freq_data.freq;
438}
439
440/*
441 * set_pstate: Sets the pstate on this CPU.
442 *
443 * This is called via an smp_call_function.
444 *
445 * The caller must ensure that freq_data is of the type
446 * (struct powernv_smp_call_data *) and the pstate_id which needs to be set
447 * on this CPU should be present in freq_data->pstate_id.
448 */
449static void set_pstate(void *data)
450{
451 unsigned long val;
452 struct powernv_smp_call_data *freq_data = data;
453 unsigned long pstate_ul = freq_data->pstate_id;
454 unsigned long gpstate_ul = freq_data->gpstate_id;
455
456 val = get_pmspr(SPRN_PMCR);
457 val = val & 0x0000FFFFFFFFFFFFULL;
458
459 pstate_ul = pstate_ul & 0xFF;
460 gpstate_ul = gpstate_ul & 0xFF;
461
462 /* Set both global(bits 56..63) and local(bits 48..55) PStates */
463 val = val | (gpstate_ul << 56) | (pstate_ul << 48);
464
465 pr_debug("Setting cpu %d pmcr to %016lX\n",
466 raw_smp_processor_id(), val);
467 set_pmspr(SPRN_PMCR, val);
468}
469
470/*
471 * get_nominal_index: Returns the index corresponding to the nominal
472 * pstate in the cpufreq table
473 */
474static inline unsigned int get_nominal_index(void)
475{
476 return powernv_pstate_info.nominal;
477}
478
479static void powernv_cpufreq_throttle_check(void *data)
480{
481 struct chip *chip;
482 unsigned int cpu = smp_processor_id();
483 unsigned long pmsr;
484 int pmsr_pmax;
485 unsigned int pmsr_pmax_idx;
486
487 pmsr = get_pmspr(SPRN_PMSR);
488 chip = this_cpu_read(chip_info);
489
490 /* Check for Pmax Capping */
491 pmsr_pmax = (s8)PMSR_MAX(pmsr);
492 pmsr_pmax_idx = pstate_to_idx(pmsr_pmax);
493 if (pmsr_pmax_idx != powernv_pstate_info.max) {
494 if (chip->throttled)
495 goto next;
496 chip->throttled = true;
497 if (pmsr_pmax_idx > powernv_pstate_info.nominal) {
498 pr_warn_once("CPU %d on Chip %u has Pmax(%d) reduced below nominal frequency(%d)\n",
499 cpu, chip->id, pmsr_pmax,
500 idx_to_pstate(powernv_pstate_info.nominal));
501 chip->throttle_sub_turbo++;
502 } else {
503 chip->throttle_turbo++;
504 }
505 trace_powernv_throttle(chip->id,
506 throttle_reason[chip->throttle_reason],
507 pmsr_pmax);
508 } else if (chip->throttled) {
509 chip->throttled = false;
510 trace_powernv_throttle(chip->id,
511 throttle_reason[chip->throttle_reason],
512 pmsr_pmax);
513 }
514
515 /* Check if Psafe_mode_active is set in PMSR. */
516next:
517 if (pmsr & PMSR_PSAFE_ENABLE) {
518 throttled = true;
519 pr_info("Pstate set to safe frequency\n");
520 }
521
522 /* Check if SPR_EM_DISABLE is set in PMSR */
523 if (pmsr & PMSR_SPR_EM_DISABLE) {
524 throttled = true;
525 pr_info("Frequency Control disabled from OS\n");
526 }
527
528 if (throttled) {
529 pr_info("PMSR = %16lx\n", pmsr);
530 pr_warn("CPU Frequency could be throttled\n");
531 }
532}
533
534/**
535 * calc_global_pstate - Calculate global pstate
536 * @elapsed_time: Elapsed time in milliseconds
537 * @local_pstate_idx: New local pstate
538 * @highest_lpstate_idx: pstate from which its ramping down
539 *
540 * Finds the appropriate global pstate based on the pstate from which its
541 * ramping down and the time elapsed in ramping down. It follows a quadratic
542 * equation which ensures that it reaches ramping down to pmin in 5sec.
543 */
544static inline int calc_global_pstate(unsigned int elapsed_time,
545 int highest_lpstate_idx,
546 int local_pstate_idx)
547{
548 int index_diff;
549
550 /*
551 * Using ramp_down_percent we get the percentage of rampdown
552 * that we are expecting to be dropping. Difference between
553 * highest_lpstate_idx and powernv_pstate_info.min will give a absolute
554 * number of how many pstates we will drop eventually by the end of
555 * 5 seconds, then just scale it get the number pstates to be dropped.
556 */
557 index_diff = ((int)ramp_down_percent(elapsed_time) *
558 (powernv_pstate_info.min - highest_lpstate_idx)) / 100;
559
560 /* Ensure that global pstate is >= to local pstate */
561 if (highest_lpstate_idx + index_diff >= local_pstate_idx)
562 return local_pstate_idx;
563 else
564 return highest_lpstate_idx + index_diff;
565}
566
567static inline void queue_gpstate_timer(struct global_pstate_info *gpstates)
568{
569 unsigned int timer_interval;
570
571 /*
572 * Setting up timer to fire after GPSTATE_TIMER_INTERVAL ms, But
573 * if it exceeds MAX_RAMP_DOWN_TIME ms for ramp down time.
574 * Set timer such that it fires exactly at MAX_RAMP_DOWN_TIME
575 * seconds of ramp down time.
576 */
577 if ((gpstates->elapsed_time + GPSTATE_TIMER_INTERVAL)
578 > MAX_RAMP_DOWN_TIME)
579 timer_interval = MAX_RAMP_DOWN_TIME - gpstates->elapsed_time;
580 else
581 timer_interval = GPSTATE_TIMER_INTERVAL;
582
583 mod_timer(&gpstates->timer, jiffies + msecs_to_jiffies(timer_interval));
584}
585
586/**
587 * gpstate_timer_handler
588 *
589 * @data: pointer to cpufreq_policy on which timer was queued
590 *
591 * This handler brings down the global pstate closer to the local pstate
592 * according quadratic equation. Queues a new timer if it is still not equal
593 * to local pstate
594 */
595void gpstate_timer_handler(unsigned long data)
596{
597 struct cpufreq_policy *policy = (struct cpufreq_policy *)data;
598 struct global_pstate_info *gpstates = policy->driver_data;
599 int gpstate_idx, lpstate_idx;
600 unsigned long val;
601 unsigned int time_diff = jiffies_to_msecs(jiffies)
602 - gpstates->last_sampled_time;
603 struct powernv_smp_call_data freq_data;
604
605 if (!spin_trylock(&gpstates->gpstate_lock))
606 return;
607
608 /*
609 * If PMCR was last updated was using fast_swtich then
610 * We may have wrong in gpstate->last_lpstate_idx
611 * value. Hence, read from PMCR to get correct data.
612 */
613 val = get_pmspr(SPRN_PMCR);
614 freq_data.gpstate_id = (s8)GET_GPSTATE(val);
615 freq_data.pstate_id = (s8)GET_LPSTATE(val);
616 if (freq_data.gpstate_id == freq_data.pstate_id) {
617 reset_gpstates(policy);
618 spin_unlock(&gpstates->gpstate_lock);
619 return;
620 }
621
622 gpstates->last_sampled_time += time_diff;
623 gpstates->elapsed_time += time_diff;
624
625 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
626 gpstate_idx = pstate_to_idx(freq_data.pstate_id);
627 lpstate_idx = gpstate_idx;
628 reset_gpstates(policy);
629 gpstates->highest_lpstate_idx = gpstate_idx;
630 } else {
631 lpstate_idx = pstate_to_idx(freq_data.pstate_id);
632 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
633 gpstates->highest_lpstate_idx,
634 lpstate_idx);
635 }
636 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
637 gpstates->last_gpstate_idx = gpstate_idx;
638 gpstates->last_lpstate_idx = lpstate_idx;
639 /*
640 * If local pstate is equal to global pstate, rampdown is over
641 * So timer is not required to be queued.
642 */
643 if (gpstate_idx != gpstates->last_lpstate_idx)
644 queue_gpstate_timer(gpstates);
645
646 spin_unlock(&gpstates->gpstate_lock);
647
648 /* Timer may get migrated to a different cpu on cpu hot unplug */
649 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
650}
651
652/*
653 * powernv_cpufreq_target_index: Sets the frequency corresponding to
654 * the cpufreq table entry indexed by new_index on the cpus in the
655 * mask policy->cpus
656 */
657static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
658 unsigned int new_index)
659{
660 struct powernv_smp_call_data freq_data;
661 unsigned int cur_msec, gpstate_idx;
662 struct global_pstate_info *gpstates = policy->driver_data;
663
664 if (unlikely(rebooting) && new_index != get_nominal_index())
665 return 0;
666
667 if (!throttled) {
668 /* we don't want to be preempted while
669 * checking if the CPU frequency has been throttled
670 */
671 preempt_disable();
672 powernv_cpufreq_throttle_check(NULL);
673 preempt_enable();
674 }
675
676 cur_msec = jiffies_to_msecs(get_jiffies_64());
677
678 spin_lock(&gpstates->gpstate_lock);
679 freq_data.pstate_id = idx_to_pstate(new_index);
680
681 if (!gpstates->last_sampled_time) {
682 gpstate_idx = new_index;
683 gpstates->highest_lpstate_idx = new_index;
684 goto gpstates_done;
685 }
686
687 if (gpstates->last_gpstate_idx < new_index) {
688 gpstates->elapsed_time += cur_msec -
689 gpstates->last_sampled_time;
690
691 /*
692 * If its has been ramping down for more than MAX_RAMP_DOWN_TIME
693 * we should be resetting all global pstate related data. Set it
694 * equal to local pstate to start fresh.
695 */
696 if (gpstates->elapsed_time > MAX_RAMP_DOWN_TIME) {
697 reset_gpstates(policy);
698 gpstates->highest_lpstate_idx = new_index;
699 gpstate_idx = new_index;
700 } else {
701 /* Elaspsed_time is less than 5 seconds, continue to rampdown */
702 gpstate_idx = calc_global_pstate(gpstates->elapsed_time,
703 gpstates->highest_lpstate_idx,
704 new_index);
705 }
706 } else {
707 reset_gpstates(policy);
708 gpstates->highest_lpstate_idx = new_index;
709 gpstate_idx = new_index;
710 }
711
712 /*
713 * If local pstate is equal to global pstate, rampdown is over
714 * So timer is not required to be queued.
715 */
716 if (gpstate_idx != new_index)
717 queue_gpstate_timer(gpstates);
718 else
719 del_timer_sync(&gpstates->timer);
720
721gpstates_done:
722 freq_data.gpstate_id = idx_to_pstate(gpstate_idx);
723 gpstates->last_sampled_time = cur_msec;
724 gpstates->last_gpstate_idx = gpstate_idx;
725 gpstates->last_lpstate_idx = new_index;
726
727 spin_unlock(&gpstates->gpstate_lock);
728
729 /*
730 * Use smp_call_function to send IPI and execute the
731 * mtspr on target CPU. We could do that without IPI
732 * if current CPU is within policy->cpus (core)
733 */
734 smp_call_function_any(policy->cpus, set_pstate, &freq_data, 1);
735 return 0;
736}
737
738static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
739{
740 int base, i, ret;
741 struct kernfs_node *kn;
742 struct global_pstate_info *gpstates;
743
744 base = cpu_first_thread_sibling(policy->cpu);
745
746 for (i = 0; i < threads_per_core; i++)
747 cpumask_set_cpu(base + i, policy->cpus);
748
749 kn = kernfs_find_and_get(policy->kobj.sd, throttle_attr_grp.name);
750 if (!kn) {
751 int ret;
752
753 ret = sysfs_create_group(&policy->kobj, &throttle_attr_grp);
754 if (ret) {
755 pr_info("Failed to create throttle stats directory for cpu %d\n",
756 policy->cpu);
757 return ret;
758 }
759 } else {
760 kernfs_put(kn);
761 }
762
763 gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL);
764 if (!gpstates)
765 return -ENOMEM;
766
767 policy->driver_data = gpstates;
768
769 /* initialize timer */
770 init_timer_pinned_deferrable(&gpstates->timer);
771 gpstates->timer.data = (unsigned long)policy;
772 gpstates->timer.function = gpstate_timer_handler;
773 gpstates->timer.expires = jiffies +
774 msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
775 spin_lock_init(&gpstates->gpstate_lock);
776 ret = cpufreq_table_validate_and_show(policy, powernv_freqs);
777
778 if (ret < 0) {
779 kfree(policy->driver_data);
780 return ret;
781 }
782
783 policy->fast_switch_possible = true;
784 return ret;
785}
786
787static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
788{
789 /* timer is deleted in cpufreq_cpu_stop() */
790 kfree(policy->driver_data);
791
792 return 0;
793}
794
795static int powernv_cpufreq_reboot_notifier(struct notifier_block *nb,
796 unsigned long action, void *unused)
797{
798 int cpu;
799 struct cpufreq_policy cpu_policy;
800
801 rebooting = true;
802 for_each_online_cpu(cpu) {
803 cpufreq_get_policy(&cpu_policy, cpu);
804 powernv_cpufreq_target_index(&cpu_policy, get_nominal_index());
805 }
806
807 return NOTIFY_DONE;
808}
809
810static struct notifier_block powernv_cpufreq_reboot_nb = {
811 .notifier_call = powernv_cpufreq_reboot_notifier,
812};
813
814void powernv_cpufreq_work_fn(struct work_struct *work)
815{
816 struct chip *chip = container_of(work, struct chip, throttle);
817 unsigned int cpu;
818 cpumask_t mask;
819
820 get_online_cpus();
821 cpumask_and(&mask, &chip->mask, cpu_online_mask);
822 smp_call_function_any(&mask,
823 powernv_cpufreq_throttle_check, NULL, 0);
824
825 if (!chip->restore)
826 goto out;
827
828 chip->restore = false;
829 for_each_cpu(cpu, &mask) {
830 int index;
831 struct cpufreq_policy policy;
832
833 cpufreq_get_policy(&policy, cpu);
834 index = cpufreq_table_find_index_c(&policy, policy.cur);
835 powernv_cpufreq_target_index(&policy, index);
836 cpumask_andnot(&mask, &mask, policy.cpus);
837 }
838out:
839 put_online_cpus();
840}
841
842static int powernv_cpufreq_occ_msg(struct notifier_block *nb,
843 unsigned long msg_type, void *_msg)
844{
845 struct opal_msg *msg = _msg;
846 struct opal_occ_msg omsg;
847 int i;
848
849 if (msg_type != OPAL_MSG_OCC)
850 return 0;
851
852 omsg.type = be64_to_cpu(msg->params[0]);
853
854 switch (omsg.type) {
855 case OCC_RESET:
856 occ_reset = true;
857 pr_info("OCC (On Chip Controller - enforces hard thermal/power limits) Resetting\n");
858 /*
859 * powernv_cpufreq_throttle_check() is called in
860 * target() callback which can detect the throttle state
861 * for governors like ondemand.
862 * But static governors will not call target() often thus
863 * report throttling here.
864 */
865 if (!throttled) {
866 throttled = true;
867 pr_warn("CPU frequency is throttled for duration\n");
868 }
869
870 break;
871 case OCC_LOAD:
872 pr_info("OCC Loading, CPU frequency is throttled until OCC is started\n");
873 break;
874 case OCC_THROTTLE:
875 omsg.chip = be64_to_cpu(msg->params[1]);
876 omsg.throttle_status = be64_to_cpu(msg->params[2]);
877
878 if (occ_reset) {
879 occ_reset = false;
880 throttled = false;
881 pr_info("OCC Active, CPU frequency is no longer throttled\n");
882
883 for (i = 0; i < nr_chips; i++) {
884 chips[i].restore = true;
885 schedule_work(&chips[i].throttle);
886 }
887
888 return 0;
889 }
890
891 for (i = 0; i < nr_chips; i++)
892 if (chips[i].id == omsg.chip)
893 break;
894
895 if (omsg.throttle_status >= 0 &&
896 omsg.throttle_status <= OCC_MAX_THROTTLE_STATUS) {
897 chips[i].throttle_reason = omsg.throttle_status;
898 chips[i].reason[omsg.throttle_status]++;
899 }
900
901 if (!omsg.throttle_status)
902 chips[i].restore = true;
903
904 schedule_work(&chips[i].throttle);
905 }
906 return 0;
907}
908
909static struct notifier_block powernv_cpufreq_opal_nb = {
910 .notifier_call = powernv_cpufreq_occ_msg,
911 .next = NULL,
912 .priority = 0,
913};
914
915static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
916{
917 struct powernv_smp_call_data freq_data;
918 struct global_pstate_info *gpstates = policy->driver_data;
919
920 freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
921 freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
922 smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
923 del_timer_sync(&gpstates->timer);
924}
925
926static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,
927 unsigned int target_freq)
928{
929 int index;
930 struct powernv_smp_call_data freq_data;
931
932 index = cpufreq_table_find_index_dl(policy, target_freq);
933 freq_data.pstate_id = powernv_freqs[index].driver_data;
934 freq_data.gpstate_id = powernv_freqs[index].driver_data;
935 set_pstate(&freq_data);
936
937 return powernv_freqs[index].frequency;
938}
939
940static struct cpufreq_driver powernv_cpufreq_driver = {
941 .name = "powernv-cpufreq",
942 .flags = CPUFREQ_CONST_LOOPS,
943 .init = powernv_cpufreq_cpu_init,
944 .exit = powernv_cpufreq_cpu_exit,
945 .verify = cpufreq_generic_frequency_table_verify,
946 .target_index = powernv_cpufreq_target_index,
947 .fast_switch = powernv_fast_switch,
948 .get = powernv_cpufreq_get,
949 .stop_cpu = powernv_cpufreq_stop_cpu,
950 .attr = powernv_cpu_freq_attr,
951};
952
953static int init_chip_info(void)
954{
955 unsigned int chip[256];
956 unsigned int cpu, i;
957 unsigned int prev_chip_id = UINT_MAX;
958
959 for_each_possible_cpu(cpu) {
960 unsigned int id = cpu_to_chip_id(cpu);
961
962 if (prev_chip_id != id) {
963 prev_chip_id = id;
964 chip[nr_chips++] = id;
965 }
966 }
967
968 chips = kcalloc(nr_chips, sizeof(struct chip), GFP_KERNEL);
969 if (!chips)
970 return -ENOMEM;
971
972 for (i = 0; i < nr_chips; i++) {
973 chips[i].id = chip[i];
974 cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
975 INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
976 for_each_cpu(cpu, &chips[i].mask)
977 per_cpu(chip_info, cpu) = &chips[i];
978 }
979
980 return 0;
981}
982
983static inline void clean_chip_info(void)
984{
985 kfree(chips);
986}
987
988static inline void unregister_all_notifiers(void)
989{
990 opal_message_notifier_unregister(OPAL_MSG_OCC,
991 &powernv_cpufreq_opal_nb);
992 unregister_reboot_notifier(&powernv_cpufreq_reboot_nb);
993}
994
995static int __init powernv_cpufreq_init(void)
996{
997 int rc = 0;
998
999 /* Don't probe on pseries (guest) platforms */
1000 if (!firmware_has_feature(FW_FEATURE_OPAL))
1001 return -ENODEV;
1002
1003 /* Discover pstates from device tree and init */
1004 rc = init_powernv_pstates();
1005 if (rc)
1006 goto out;
1007
1008 /* Populate chip info */
1009 rc = init_chip_info();
1010 if (rc)
1011 goto out;
1012
1013 register_reboot_notifier(&powernv_cpufreq_reboot_nb);
1014 opal_message_notifier_register(OPAL_MSG_OCC, &powernv_cpufreq_opal_nb);
1015
1016 rc = cpufreq_register_driver(&powernv_cpufreq_driver);
1017 if (!rc)
1018 return 0;
1019
1020 pr_info("Failed to register the cpufreq driver (%d)\n", rc);
1021 unregister_all_notifiers();
1022 clean_chip_info();
1023out:
1024 pr_info("Platform driver disabled. System does not support PState control\n");
1025 return rc;
1026}
1027module_init(powernv_cpufreq_init);
1028
1029static void __exit powernv_cpufreq_exit(void)
1030{
1031 cpufreq_unregister_driver(&powernv_cpufreq_driver);
1032 unregister_all_notifiers();
1033 clean_chip_info();
1034}
1035module_exit(powernv_cpufreq_exit);
1036
1037MODULE_LICENSE("GPL");
1038MODULE_AUTHOR("Vaidyanathan Srinivasan <svaidy at linux.vnet.ibm.com>");